This quest can be obtained from Shopkeeper Pleel in Berg. She will ask you to deliver a ledger to Shopkeeper Lyda in the city of Monsoon. The city of Monsoon is located in the region of Hallowed Marsh and can be accessed from the region of Chersonese and Enmerkar Forest, as shown on the map below.
When you reach the city, head directly north until you see the Soroborean Caravanner on your left. From here, go through the door a little further on, leading to the Merchant’s Promenade. Here you will find Shopkeeper Lyda.